This invention relates to a two-stroke, spark ignition, internal combustion engine, with two, three, four or six cylinders. Fuel injection is provided by means of combustion gases and no fuel pump is employed. In this engine the working spaces of cylinders are interconnected by means of ducts in such a manner that during the working stroke a small amount of high pressure combustion gases enters the working space, after the duct port is uncovered by the piston, carrying along a predetermined amount of fuel, thereby effecting the injection.
The engine according to this invention operates as follows: fuel injection is accomplished, with the absence of any fuel pump, in a three-cylinder two-stroke engine in which the cranks are spaced 120 deg. apart. The working space of each cylinder is connected by two small bore ducts with the other cylinders and each of these ducts has the inlet in the cylinder wall of one cylinder above the piston midstroke and the injection outlet in the cylinder wall of the other cylinder below the midstroke. To accomplish pumpless fuel injection in a four-cylinder two-stroke internal combustion engine, the cylinders are arranged in series or in the form of a V, in such a manner that the working spaces of cylinders, in which ignition occurs every 180 deg. of crankshaft revolution, are interconnected by gas ducts to which the fuel is delivered at a controlled rate so that the exhaust gases of one cylinder carry the fuel and accomplish the injection in the other cylinder in which the ignition takes place after an additional crankshaft revolution of 180 degrees. The exhaust gases from this second cylinder inject the fuel in the first cylinder after an additional crankshaft revolution of 180 degrees.
This invention accomplishes pumpless injection of fuel in a six-cylinder, two-stroke engine with the cylinders arranged in series or in the form of a V in such a manner that the working spaces of cylinders are interconnected by gas ducts to which the fuel is delivered at a predetermined rate; each pair of cylinders in which ignition occurs every 180 deg. of crankshaft revolution is interconnected, or each three cylinders in which the ignition occurs every 120 deg. are interconnected by means of ducts. Each of the said ducts has the inlet in the cylinder wall of one cylinder above the piston midstroke and the injection outlet in the other cylinder below the piston midstroke.
A common characteristic trait of several embodiments of the invention is the fact that the axes of symmetry of injection ports are directed towards the inlets of precombustion chambers, and that the spark plug is located in the precombustion chamber within the conical surface or are defined by the injection stream, of the fuel introduced into the precombustion chamber gas passages; open fuel meters are provided which consist of a metering chamber with a capacity greater than the maximum charge of fuel needed for one working cycle and inlet and outlet ducts each with passages of a diameter less than 1/2 of the gas duct bore. At the place where fuel meter is located; a solenoid-operated fuel valve can be also installed. Apart from this, a further common characteristic trait is that the fuel supply ducts to the meters are preheated by means of combustion gases and that the gas duct inlet ports widen with an off-set in the proximity of the cylinder bearing surface.
The hitherto known solutions of two-cylinder internal combustion engines with pump-less injection of fuel, in which the working spaces are interconnected by gas ducts, do not provide for any system of three-and more cylinder engines and do not specify the direction of the injection stream, location of spark plug and fuel meters.